Clay County is a county located in the U.S. state of Missouri. As of the 2010 census, the county had a population of 221,939,[1] making it the fifth-most populous county in Missouri. Its county seat is Liberty.[2] The county was organized January 2, 1822, and named in honor of U.S. Representative Henry Clay from Kentucky, later member of the United States Senate and United States Secretary of State.[3][4]

Clay County is part of the Kansas City, MO-KS Metropolitan Statistical Area and contains many of the city’s northern suburbs, along with a substantial portion of the City of Kansas City.